Best and Most Efficient Water Heater

We need a new electric water heater, 50 gallon. We call a bunch of different plumbers, and they all "recommend" the ones they carry. A bunch of them recommend the A.O. Smith (but the reviews I've read hate this brand). Others say the GE is not a good brand because it's a "thin tank". Any recommendations? And what warranty should be standard?

There are several questions you need to ask about electric heaters.
what is more important to you, Fast Hot water, energy conservation, warranty?
a regular tank type with two elements will give the best recovery of a tank type hot water heater at about 83% efficiency (Cheapest)
a hybrid tank type will give much better efficiency 230% but takes much longer to recover, unless it uses the backup element (expensive)
electric tankless 99% efficient need a lot of power most homes don't have enough unless built with tankless in mind
as far as water heater tanks, they are pretty much the same 6 and 12 year warranties. If you want them to last forever change the anode every two or three years depending on the water conditions and install a expansion tank to help reduce metal fatigue.
Good Luck
George